Techniques of enzymatic cytochemistry used in hematologic cytology and widely accepted in the classification of acute leukemias, were adapted to biopsy material of decalcified bone marrow included in paraffin. In Paraguay, the Hematopathology Section of the Department of Pathology of the Health Sciences Research Institute (IICS) introduced these techniques for the study of cyto and hystological materials of hematologic pathologies. Currently, almost all the material is concentrated for the anatomopathological study of these pathologies in the country. This study describes the morphological and cytohistochemical findings in 374 biopsies of bone marrow, 167 bone marrow aspirates and 114 peripheral blood smears during five years (1997-2002) of 370 hematological patients of different hospitals of the country using different enzymatic cytohistochemical schemes. Besides, the sensitivity, specificity and diagnostic concordance between the clinico-hematologic and anatomopathological methods were analysed. Most patients were male adults and the most frequent pathologies were: chronic lymphoproliferative processes, Hodgkin's and non-Hodgkin's lymphomas (58 cases), bone marrow aplasias (47 cases), acute lymphoblastic leukemias (40 cases), myeloid leukemias (47 cases), chronic myeloproliferative diseasses (31 cases), myelodysplasias (14 cases), metastasis (10 cases) and monoclonal gammapaties (7 cases). Ninetyeight cases corresponded to reactive bone marrow hyperplasias and 12 were normal. Hemorrhagic and small (< 5 mm) materials were excluded. The concordance between the clinico-hematologic and anatomopathological diagnostic methods was low (kappa index 38%), the sensitivity of the clinico-hematologic method was 54.58% and the specificity was 5.55% which show the importance of the use of bone marrow biopsies and hematologic cytology together with special and systematic techniques to achieve precise, final and confirmatory diagnosis in great part of the hematologic pathologies.